This invention relates to a method and apparatus for controlling the ripening of fresh produce, particularly fruit such as bananas.
Boxes of bananas and other imported produce are usually transported from packing facilities to ships in non-air-conditioned trucks or railroad cars, transfer of the boxes being accomplished individually or in groups held by pallets. In the ships, the banana boxes are usually placed in refrigerated chambers wherein cool air is supplied through slotted decks and returned to cooling units located in spaces above the tops of the boxes. The boxes are generally stacked vertically so that the cool air can travel through vent slots from the bottoms to the tops of the boxes. On occasion the boxes of fruit are loaded into air-conditioned containers at the packing facilities and transported aboard special container ships.
Upon discharge from a ship, banana boxes are usually loaded directly into air-conditioned trucks or air-conditioned railroad cars for transport to ripening facilities, customers or processors. In the trucks, the conditioned air is generally supplied from a unit at the front of the trailer and is blown across the top of the load to the back of the trailer. Some trucks are provided with slotted floors which facilitate access of air to the bottoms of the boxes.
At processing facilities, the banana boxes are placed in specially designed ripening rooms provided with insulated, gas tight wall and roof panels. The rooms are generally 30 or 40 feet long and 10 to 15 feet wide and have heights accommodating stacks of boxes in racks of three tiers and two tiers or stacks of boxes without racks. Each room contains an air handling unit which cools or warms the air and which, by means of large fans, circulates the air around the room. The air flows across the boxes at the tops of the stacks and returns through the stacks to an intake of the air handling unit. The temperature of the air in such a room is controlled in accordance with a ripening schedule, and ethylene gas is dispersed in the room at a predetermined time to facilitate uniform ripening.
In the ripening rooms, the banana boxes are air stacked on pallets (i.e., disposed on pallets in stacks such that boxes in the same horizontal layer are spaced from each other) and placed in racks or on the floor. The boxes in a refrigerated container of bananas must be removed individually and air stacked on pallets placed on the floor of single tier ripening rooms or in racks.
In one pressure cooling system, a false end wall in a ripening room is provided with exhaust fans which create a low pressure plenum between rows of palletized boxes, the space between the boxes being covered with canvas material at the top and along an end opposite the fans. The conditioned air from the ripening room then travels horizontally through openings in the sides of the boxes, over the fruit therein and through the low pressure central plenum and the exhaust fans.
It is known in different applications to wrap stacks of boxes of dry goods with sheets of synthetic resin material to stabilize and lend rigidity to the stacks and to secure the boxes to underlying pallets. This same technique has been used on stacks of banana boxes for the same reasons, as well as for insulating the bananas from environments with especially low temperatures. To avoid defeating the insulation objective, any holes in the bottoms of the banaza boxes are blocked, thereby preventing the passage of air vertically through the banana box stacks.
An object of the present invention is to provide an improved method and apparatus for controlling the ripening of produce, particularly fruit such as bananas.
Another, more particular, object of the present invention is to provide such a method and apparatus with which palletized loads of fruit or other produce may be temperature controlled or ripened without restacking or individual handling of the boxes, and particularly without air stacking of boxes on pallets.
A further object of the present invention is to provide such a method and apparatus in which conditioned air may be provided in virtually any location, eliminating the necessity for air-conditioned warehouses or rooms.
Another object of the present invention is to provide such a method and apparatus in which a ripening room may be converted to pressure cooling with less expense than with known systems.
Yet another object of the present invention is to provide such a method and apparatus which enables the pressure cooling of produce in palletized boxes placed in racks.